I have seen many feature requests like SMS MMS sync requested here, also I do have some of my own like to have Notes. Thought those are nice features to have, probably they are out of the scope of your product as it was initially intended, so I would suggest that you could take advantage of you nice Sync engine you have that works also in USB mode and add an Android application that can be used to take notes and sync that with a special folder in thunderbird? or Myabe MS-OneNote (OneNOte would be REALLY nice), maybe the SMS and MMS could be synced to thunderbird.